Distinguishing small cell carcinoma from non-small cell carcinoma of the lung: correlating cytologic features and performance in the College of American Pathologists Non-Gynecologic Cytology Program.

Abstract

Abstract Context.—The cytologic features of small cell carcinoma of the lung are well described. Nevertheless, some small cell carcinomas may be difficult to reproducibly distinguish from non–small cell carcinomas, and this distinction carries significant clinical importance. Objective.—To correlate the cytologic features of individual cases of small cell carcinoma of the lung in fine-needle aspiration specimens from the College of American Pathologists Non-Gynecologic Peer Comparison Cytology Program with the frequency of misclassification as non– small cell carcinoma. Design.—We reviewed 1185 interpretations of 23 different cases of small cell carcinoma in lung fine-needle aspiration specimens and correlated the cytologic features noted in these cases with performance in the program. Results.—Cases were divided into those that were frequently misclassified as non–small cell carcinoma (at least 10% of the responses, 11 cases) and those that were infrequently misclassified as non–small cell carcinoma (<5%...